I recently acquired a Ruger 9mm (takedown) carbine. After shooting it a couple of times, I decided that the sights could be improved by moving the rear sight to the back of the receiver rail. Doing so almost doubles the sighting radius which should improve accuracy. I bought a Leapers adjustable rear peep sight, mounted it on the rail and checked adjustment by sighting thru the new sight, the original rear sight and centered the front sight. Everything seemed to line up so I removed the original rear sight. A trip to the range showed that even with the new rear sight all the way down, the carbine was shooting a bit high. Since I couldn't lower the rear sight any more, I made a curved aluminum spacer to fit between the barrel and front sight. The spacer is about 1/8" thick which is more than needed so I will most likely have to raise the rear sight a bit. To make the front spacer, I found a long socket that is the same diameter as the barrel, clamped a piece of aluminum to the socket with a set of locking pliers and heated the aluminum with a propane torch. Once it got warm enough, I curved the aluminum around the socket. After letting the metal cool for a few minutes, I placed the front sight on top of the now curved aluminum and marked around the front sight to show where it needed to be trimmed. A little work with a hack saw and some files produced just the right piece! Next, I placed the sight on top of the curved aluminum piece and marked the holes for the two mounting screws. I used a drill press to drill out the holes and used a piece of sand paper and a file to clean up the holes. I had to replace the 6-48 screws with two that are 1/8" longer to allow for the spacer. A little work with an allenwrench and it was all back together again. I still have to blacken the spacer and will do so when the bottle of Alumni-Black arrives. Will post some pictures when it is completed.